Carburetor



P 9 1- c. L. STOKES 1,799,486

' CARBURETOR Filed Nov. 24. 1923 Patented Apr. 7,. 1931 UNI ED. I'STTATESV PATENT"? oFFic CHARLES LAWRENCE s'roxns, or Los ANGELES, CALIFORNIA, Ass'IeNon 'ro cua'rrsia cam, TRUSTEE, or emmoon, ILLINOIS CARBURETOR Application filed November 24, 1923. Serial No. 676,864.

My invention relates to improvements in apparatus for controlling the fuel feed to an internal combustion engine, whereby efliciency in starting is obtained and also whereby pending applications S. N. 626,990,. filed March 22nd, 1923, which matured into Patent 1,694,801 granted Dec. 11,1928, and N. 644,923, filedJune 12th, 1923, which matured into Patent 1,750,766 granted Mar. 18, 1930, the principal of which includes the use of a Bourdon tube or diaphragm which is expanded, or contracted, according to variations .in

engine vacuum.

A further object is to automatically con trolthe choker in a. carburetor according to the engine vacuum, and also'in accordance with the temperature of the air passing through the carburetor.

Referring to the drawings, which the I 11' to the carburetor is controlled by a certain same numbers indicate like parts El 1 isa section and part view of any wellown design of carburetor with my improvements attached thereto.

.Fig'. 2 is a view'and lines A-A of'Fig. 1. 1

Fig. 3 is a view and part section of an alternative.

In Fig. 1, the carburetor 1 contains anmi xing chamber 2 for fuel and air, an air, inlet 7 3 and a throttle or butterfly valve 4 for controllin the speed of the engine. Hot air is genera ly passed to the air inlet 3 through a pipe (not shown) connected to the engineexhaust pipe. ,The carburetor 1 is attached to an internal combustion engine in any well known manner and for. starting the same in cold weather it is customary to close passage 3 by a choker valve'5, whereby a large volume of fuel will be drawn from a float chamher 8 through a fuel passage 7 and nozzle 6, and the float chamber 8 is constructed in any well known manner and supplied with fuelpart section along the v containin through a pipe 9. The choker valve 5 normally-is retained in a horizontal position in the air inlet 3 by means of a spring 23, and the choker valve 5 is mounted on 'a spindle 22, one end of which extends outside of the air inlet 3 with a lever 24 attached theretofor manually controlling the operation of chok-. in the engine. a

11. order to perform the function of choking automatically, I provide a casing- 10,

which is air-tight except for the connections to be hereinafter described, and the casing 10 is placed on the upper side of the air inlet 3.. The upperend of the casing 10 isclosed'by a plug 13 to which is soldered a bellows, or expansible diaphragm 151, and the lower end of the bellows 14 is closed tight by a discI15-having a central stern 16terminatingin a push rod .17. The central stem 16 is guided by a boss 18, and the push rod 17 normallyjust about rests on one edge of the choker valve 5 when the choker valve 5 is in a horizontal position.

A pipe 11 connects the interior of the easing 10 with the carburetor, which is really a part of the enginemanifol'd, on the engine side of valve 4 and the entrance of the'pipe sized orifice 12, which orifice will vary in size with the conditions to be met in any par 3 ticular carburetor or engine.

On the interior of the casing 10 is a boss 19 an inwardly seating valve 20, which is eld to its seat by a lig t spring 21 and the inner head of the valve 20 is placed a redetermined distance from the lower face v o the disc 15.

The operation is as follows I- Upon starting the engine to which the carburetor 1 isattached, the butterfly valve 9 4 is generally substantially closed so that a very high vacuum prevails on e engine side of the butterfly valve 4. N rmally, in cold weather there will be insuflicient fuel provided through the nozzle 6, or any auxiliary idling nozzle (not shown), to start the engine and it is customary to create a high vacuum in the mixing chamber 2 by manually closing the choker valve 5 through the operation of the lever 24, whereby a fairly large volume of fuel is sucked from the nozzle 6 until the engine is started and this operation must be repeated from time to time until the engine reaches a normal running temperature.

- In operation, the high engine vacuum through the orifice 12 is applied through the pipe 11 to the interior of the casing 10, whereupon the gaseous fluids within the bellows 14 are caused to suddenly expand and the downward movement of the disc 15 caused thereby forces the push rod 17 against the choker valve and closes the same a predetermined distance. The gaseous fluids within the bellows 14 may be air, but when the bellows 14 is closed air tight. I prefer to use a volatile fluid such as ether, casinghead gasoline, liquid sulphur dioxide, or any other suitable liquids which give a desired expansion curve, so that an expansion and contraction of the bellows 14 may be had according to temperature, as Well as vacuum.

The sudden downward movement of the bellows 14 is due to the fact that the valve 20 is normally closed at a predetermined temperature and the sudden downward movement of the bellows 14 causes the disc to strike the inner head of the valve and thereby admits a certain amount of air through the port 26 to the interior of the ca sing 10 responsive to the vacuum being ap- V plied through pipe 1.1.

In this manner my apparatus is designed so that in very cold weather when the contraction of the bellows 14 is a maximum, the first initial application of vacuum to the bellows 14 will cause the choker valve 5 to close a maximum distance thus inducing a large flow of liquid fuel through the nozzle 6. Thereafter the choker valve 5 is then partly opened a predetermined distance, because the disc 15 will have struck the inner head of the valve 20 thereby admitting a certain amount of air therethrough and partially breaking the vacuum applied through the pipe 11.

l he hot air tube (not shown) is applied to the outer end of the air inlet 3, and as the en gine warms up there will be a further expansion of the bellows 14, due to the warm air being admitted through the valve 20 and acting upon the gaseous. fluids in the bellows 14, and thus the valve 20 will be further opened so that at a maximum given temperature, the vacuum applied through the pipe 11 will be substantially broken by the air being admitted through the valve 20, thus leaving the choker valve 5 wide open and in a horizontal position.

It. may thus be seen that for all conditions of temperature, the engine vacuum may be utilized to operate choker 5 in conformity with the amount of fuel necessary for engine operation,-and it will also be noted that the action of my apparatus is very useful in accelerating because, it being well known that extra fuel is necessary for quick acceleration,

if it is assumed that acceleration is desired from closed to wide open throttle, the high vacuum being applied through the pipe 11 will have closed the choker valve 5 a certain distance and on suddenly opening the throttle or butterfly valve 4 wide, there is a slight lag in the opening of the choker valve 5, so that temporarily a higher vacuum is placed on the nozzle 6 thus giving the accelerating charge.

Referring to Fig. 3, instead of using the diaphragm 14 to be expanded by variations in tei'nperature, the interior of the. bellows 14 is opened to atmosphere through an orifice 25 in cover 13, so that the movements of the bellows 14 are solely due to the effect of the vacuum being applied through the pipe 11. The degree of this vacuum, however, is still thermostatically governed by the admission of air through the port 26, but in the present instance the port 26 is opened or closed by a valve 27 which is actuated by a bi-metal thermostat 28 which is suitably attached inside of the casing 10.

The movement of the valve 27 is principally governed by the temperature of the air passing through the air inlet 3 and the valve :27 is also slightly affected by the vacuum being applied to the interior of the casing 10, so that when the valve 27 is designed for predetermined temperatures and vacuums, the admission of air through the port 26 may be easily regulated and thus the movement of the bellows 14 will be controlled in conformity with the operation hereinbefore de-. scribed for moving the choker valve 5 and controlling the flow of fuel through the nozzle 6.

I claim 1. A carburetor for internal combustion engines comprising an induction chamber, a throttle valve therein, a fuel nozzle, an intake for supplying air to said induction chamber, a choke valve in said intake, a cylinder, a movable pressure responsive memher in said cylinder adapted to actuate the choke valve, a tube connecting the cylinder with the induction chamber above the throttle valve, and a thermostatically controlled valve for admitting air to the cylinder to render said member less effective when the engine temperaturehas increased.

2. A carburetor for internal combustion engines comprlslng an induction chamber, a-

throttle valve therein, a fuel nozzle an'dintake for supplying air to said induction chamber, a choke valve in said intake, a cylinder, a movable pressure responsive member in said cylinder adapted to actuate the choke valve and a valve in said cylinder having a resilient thermostatic member for yieldingly rendering the valve seated whereby the valve is rendered responsive to pressure and temperature conditions to govern the movements of said movable member.

3. A carburetor for internal combustion engines comprising an induction chamber,

a throttle valve therein, a fuel nozzle and intake for supplying air to said induction chamber, a choke valve in said intake, means tending to maintain said choke valve in open position, a cylinder, a movable pressure-rem sponsive member in said cylinder eflective to move said chokevalve from its open position and a thermostatically controlled valve for admitting air to said cylinder to render said member less effective when the engine tem- 'perature has increased.

4. A carburetor for internal combustion engines comprising an induction chamber, a

' throttle valve therein, a fuel nozzle and intake for supplying air to said induction chamber, a choke valve in said intake, means tending to maintain said choke valve in open position, a cylinder, a movable pressure-responsive member in said cylinder effective to move said choke valve from its open position and a thermostatically controlled valve for admitting air to said cylinder to reduce the effectiveness of said member onsaid choke valve when the engine temperature has increased.

5. A carburetor for internal combustion engines comprising an induction chamber, a throttle valve therein, a fuel nozzle and intake -for supplying air to said induction chamber, a choke valve in said intake, a cylinder, a movable pressure-responsive member in said cylinder, a tube connecting the cylinder with said induction chamber above said throttle to initially govern the movement of said member by engine suction for actuating said choke valve, and a thermostatically .controlled valve for admitting air to said cylinder to render said member-less, effective when the engine temperature has increased.

6. A carburetor for internal combustion 5 engines comprising-an induction chamber, a

throttle valve therein, a fuel nozzle and intake for supplying air to said induction chamber, a choke valve in said intake, a cylinder, a movable pressure-responsive member in said cylinder, a tube connecting said cylinder with said induction chamber above said throttle to initially govern the movement of said member by engine suction for actuating said choke valve and a valve in said cylinder having a resilient thermostatic member for yieldingly rendering the valve seated wherey the valve is rendered responsive to pressure and temperature variations to govern the movements of said member.

7. A carburetor for internal combustion engines comprising an induction chamber, a throttle valve therein, a fuel nozzle and intake for supplying air to said induction valve in open position, a cylinder, a movable pressure-responsive member in said cylinder eifective to move said choke valve from its open position, having a resilient thermostatic mem er for yieldingly rendering the valve seated wherey the valve is rendered responsive to pressure and temperature conditions to govern the movements of said movable member, said choke valve followin the movements of said member under the i uence of said spring.

Signed at Wilmington, in the county of and a valve in said 0 linder I Los Angeles, and State of California, this 6th day of November, A. D. 1923.

CHARLES LAWRENCE STOKES.

chamber, a choke valve in said intake, a.

65 spring means tending to maintain said choke 

